1. Field of the Invention
The present invention relates to a radiographic image detection apparatus that detects a radiographic image by irradiating a subject with radiation. Further, the present invention relates to a method for controlling the radiographic image detection apparatus.
2. Description of the Related Art
Conventionally, various kinds of radiation detectors (radiographic image detectors) have been proposed and practically used in medical fields, and the like. The radiation detectors store radiographic images related to subjects by irradiation with radiation that has passed through the subjects. One of the examples of such radiation detectors is a radiation detector using amorphous selenium, which generates charges by irradiation with radiation. Further, a so-called TFT-readout-type radiation detector, which uses an active matrix substrate, has been proposed. The active matrix substrate includes a plurality of divided electrodes, a plurality of storage capacitances (capacities) that store charges collected by each of the divided electrodes, and a plurality of TFT switches for reading out the charges stored in each of the storage capacitances.
In the radiographic image detectors, defect pixels are generated at some pixels, or dirt, dust or the like adheres to a top plate or the cover of the detector in some cases. In such cases, a defect region in which correct image information is not obtained is present in the radiographic image detector, and the presence of the defect region deteriorates the image quality of the radiographic image. Therefore, various methods have been proposed to prevent deterioration of the image quality caused by the defect region.
For example, Japanese Unexamined Patent Publication No. 11(1999)-126890 (Patent document 1) discloses a structure in which a radiographic image detector is replaceable for each predetermined unit element holder. In the radiographic image detector, when a defect is generated in a unit element holder, the unit element holder is replaced or repaired. Further, Japanese Unexamined Patent Publication No. 2005-324015 (Patent document 2) discloses a method for interpolating image data of a defect pixel based on image data of other pixels adjacent to the defect pixel.
Further, besides the techniques disclosed in Patent documents 1 and 2, a method for preventing deterioration of the image quality caused by the defect by moving the radiographic image detector has been proposed (please refer to Japanese Unexamined Patent Publication No. 2000-134539 (Patent document 3) and Japanese Unexamined Patent Publication No. 2003-156565 (Patent document 4) for example). Patent documents 3 and 4 propose radiography of a subject (a radiography target) by using normal pixels, other than the defect pixel, by moving the radiographic image detector relative to the subject.
However, in Patent documents 3 and 4, it is necessary to move the radiographic image detector to different positions and to perform radiography a plurality of times at the different positions to obtain a single radiographic image. Therefore, there is a problem that the dose of radiation that irradiates the subject becomes high.